Electromagnetic relay



Feb. 27, 1951 G. D, oLssoN ELECTROMAGNETIC RELAY A Filed Aug. 19. 1946 a ffy 2/ Patented Feb. 27, 1951 ELECTROMAGNETIC RELAY Gunnar Daniel Olsson, Stockholm, Sweden Application August 19, 1946, Serial No. 691,629 In Sweden August 30, 1945 1 Claim.

The present invention relates to an electromagnetic relay in the type of a solenoid having a magnetic core which is movable into the coil and out of the same.

The invention has for its object to create an electromagnetic relay of said type which has a substantial delay between that moment in which the coil is switched into the circuit, and that moment 1n which the contacts are actuated. Another object of the invention is to create such a. relay in which said delay is effected without the use of complicated time mechanisms or other complicated delay mechanisms. A further object is to make the delay equal in both directions of movement, thus equal for breaking and closing the circuit. A still further object is to attain a simple construction and a f reliable operation.

One embodiment of an electromagnetic relay according to the invention is by way of example illustrated in the annexed drawing.

Fig. 1 shows a vertical central section through the relay, seen in lateral direction.

Fig. 2 shows a front elevation of said relay, thus seen from the the left hand in Fig. 1.

Fig. 3 shows a plan view of the relay according to Figs. 1 and 2. l

Fig. 4 shows the delay mechanism of the relay according to Figs. 1-3, seen from the bottom side.

Fig. 5 shows an elevation of a delay mechanism according to another embodiment.

Fig. 6 shows an elevation of the delay mechanism according to a third embodiment.

An electromagnetic relay according to the invention is characterized by the combination of a. member coaxial to the solenoid, which member is, by the axial displacement of the core, caused to rotate in either direction according to the sense ofY said displacement, and is adapted, at the end of this rotation, to cause a sudden actuation (make or break) of a number of contact pairs in'either direction; with means adapted to delay said rotation, independently of the sense of the same. These means of delay are preferably such, thatV they are disengaged, viz. brought out of action immediately before the rotatable member enters into the position in which the contacts are actuated.

The frame of the relay comprises an angular plate I, to which a magnetic coil 2 is attached. In the frame also a bush 3 of magnetic material is secured. This bush extends through the central portion of the coil 2. Said bush has in its lower portion a recess, in which the magnetic core 4 is introduced when the coil is excited.

The core 4 carries a coaxial pin or shaft 5, which extends through the bush 3 and the upper end portion of which is made as a helically Wound strip 6. This strip constitutes a screw spindle having a greatV pitch and engaging a slot 8 in a bridge I extending over the coil. In the embodiment shown the arrangement is such, that the core 4 together with the pin 5 and the screw spindle 6 makes one complete revolution when the core moves axially from one of its two end positions to the other. The upper end of the screw spindle 6 is attached to the inner end of a helical spring 9, the outer end of which is attached to the bridge '1. The spring 9 is arranged in such manner, that its tension is increased when the core is attracted by the coil. 'I'he energy thus stored is liberated when the coil 2 is switched out of the circuit, whereby the core is returned to the position of rest.

On the bridge I a body or block Il) is securely mounted. This body consists of an insulating material and carries the bridge 1. 'Ihe body I 0 carries also the connecting terminals II, I2

for the coil 2 as well as two contact springs I3, I4 and the corresponding terminals I5, I6. The springs I3, I4 are held against the circumference of a circular disc I'I, which consists of insulating material and is rotatably mounted on a pin I 8, parallel to the axis of the solenoid and attached to the frame. The disc II carries a shoulder or a projection in the shape of an axially extending pin I9 as well as two contact members 20, which are provided in the edge of said disc in positions diametrically opposite each other. The contacts are grounded to coincidence with the cylindrical surface of the disc and they constitute contact surfaces cooperating with the contact springs I3, I4. The contact members 20 are electrically connected with each other by means of a metal bail or bow 2|. Immediately below the screw spindle 6 the shaft 5 carries a radial projection 22 which extends below the contact disc I'I and is adapted to cooperate with the pin I9 in such manner, that the contact disc I'I is suddenly moved into the new end position, when the core 4 reaches its upper or lower end position, whereby the contacts are actuated.

As will be apparent from Figs. l and 4, an arm 23 consisting of a spring is attached to the lower end of the core 4. This resilient arm carries a brake member 24 on its outer end. A ring or a drum 25 is arranged concentrically around the core 4. The brake member 24 is, by the centrifugal action during the rotation of the core 4, forced into engagement with the internal surface of the drum, so that the rotation of the core is braked up. The drum is provided with a recess 26 in a position corresponding to the zero or end position of the rotatable member. 'Ihus the braking action will cease immediately before the rotating member enters into the end positions, so that the rotation thereby is accelerated to'cause asudden actuation of the contacts.

The electromagnetic relay thus described operates in the following manner.

When the coil 2 is energized, the core 4is-attracted. During the passage of the screw spindle 6 through the slot 8 the rotatable-member 4,5, 6; 15

is rotated. Thereby the brake body 2.4 is, by

centrifugal action, moved outerwardswin radial.

direction and engages the internal surface of the brake drum, so that the rotating of the core is. delayed. When the core approaches its upper end position, the body 24 has arrived-at the recess 28; Then the movement of thecore is acceler. ated, whereby a sudden or abrupt closing of the circuit is effected over the springs I3, I4', the con-,- tacts 2,9; and the bail 2 I, when the corereaches the upper end position andv they projection 22 strikes. the pin I9 to-operate the disc I'I. When the current through the coil 2'is interrupted, the coilv is deenergized and the spring 9- will move the core 4 back into the position of rest (the. lower end position), the core now being rotated in the opposite direction. Also during the rotation of thercore 4 in this direction the members 24,725 will delay the core. The circuit over the ele-A ments I3, 29, 2|, 2D', I4 is still closed. When the core approaches the position of rest, the brake. member 24 will reach the recess 29, so that then' the rotation is accelerated. Whenv the. driving. member 22 engages the pin Illandoperates. the. disc I'I, an abrupt interruption of the circuit-,is obtained (Fig. 3). Evidently, the relay may be. operated by direct current as well asV by alternating current.

Instead of the delay mechanism according to. Figs. 1 and 4 the delay mechanism as. shown in Fig. 5 may be used. The delay mechanism in this embodiment comprises a disc 28. which is of a comparatelygreat Weight and which is rotat-A ably mounted upon a stationary pin 29 and is. connected with the core 4 by means. of a-coaxial. helical spring 38; On account of therinertia ofv the disc 28'this disc is not driven duringthe first part of the rotation of theV core 4, the rotation of the core being delayed. During this first part` of the rotation of the core the spring 30 is tensioned until a value is attained, at which the.

spring overcomes the inertia of the disc 28. New

the disc is rotated under the actionl ofthe energy stored in the springr30. If the value of the initial tension of the spring is such, that the spring. is. released immediately before the core hasl reachedl its end positions, the remaining rotary .movement of the core is accelerated, whereby. an abrupt actuation of the contacts is attained-.

In the embodiment of the delay mechanismas. shown in Fig. 6, the core 4 is connected. witha a frictional disc 33 resting upon the inertia disc 32, by means of a coupling arm 34 radially projecting from the core 4, and a vertical coupling pin 34, vertically mounted upon the friction disc. The pin 35 is coupled with the arm 34 in such manner, that an axial displacement of the core in relation to the disc 33 is possible, whereas rotation of these members in relation to each other isv prevented. The disc.;32 is rotatably,v mounted on ax pin 36', which is securely: arranged in the frame. The disc 32 bears upon a shoulder 3l and the disc 33 is centered upon the pin 38. Two stationary stops 38, 39 are arranged in such positions, that they, by engagement with the arm 34, will. stopfthemotation of the core 4 in each end position. Then. the disc 32 is successively arrested` by the friction against the disc 33.

In the relay according to the embodiment, by wayof. example, described above and illustrated in the drawing, the rotatable member consists of the magnetic` core and the-shaft: whichy is rmly connectedtherewith andthe endportion of. which is provided.- with: a.. screw spindle.. inv engagement with a stationary plate.

TheA relay. accordingto@A thef invention especially. adapted .fon the interruption off. a closed.

circuit with. aA substantial...delay`v but, of.-l course; may beused'-y also, 'ta-close. openl circuits.

The `invention isfnotrestrictedfto the embodiment shown, manymodifications being possible without` departing from the. principleY of the invention.

What Lclaimv is.;v

An electromagnetic-.relay of; the.A solenoid?, type.,

comprising, in combination, a coil, a magnetic core. movableinto. the' coil y and'. out; ofV the .same.

arotatable insulating.- disc..the axis of whiclnisv substantially parallel to the axis of the solenoid,- a.- number of... contacts securely. mounted.. on the insulatinggdisda numbero-isationary spring con-.- tacts cooperating. with.. this. contact disc,v av shoulder onthe. contact. disc, a-rotatable member coaxial to the.coilwhich member isadapted, Aby the .-axial .displacement-. ofthe-core, tobe rotated in either directiomaccording to..=th.e.sense. ofsaid.

displacement.. aprojectionon the rotatablev member which projection is adapted.' near, the end. ofv said rotation,to. engage said.shoulder and actuate-the.. contacts in eitherl directionand, means adapted ,to delay. said rotationr 'independentlyof the sense of the same...

GUNNAR i DANIEL OLSSON.

REFERENCES. CITED" The,v following referenceszare of: recordgingthev le; of misc-patent i.

UNITED STATES PATENTS Number Name. Date,

571,723. De-Mott --.Noi/2 1'7, 189.6. 880,617. Bach Mar. ,3. 19.08`

1,218,123. Severy Mar. 6,191.7* 1,229,232 Coates June..12, 1917 2,061,511 Edmunds Nov...17;,19361 2,319,279. Watkinsv May 18, 19.431 

